1. Field of the Invention
The invention relates to a high-power radiator, in particular for ultraviolet light, having a discharge space filled with filler gas emitting radiation under discharge conditions, having electrode pairs which are connected in pairs to the two poles of a high-voltage source, at least one dielectric material which adjoins the discharge space lying between two electrodes at different potentials.
In this respect, the invention is related to a prior art as emerges, for instance, from the EP Application 87109674.9 or the U.S. Pat. No. 4,837,484.
2. Discussion of Background
The industrial use of photochemical processes greatly depends on the availability of suitable UV sources. The classic UV radiators supply low to medium UV intensities at some discrete wavelengths, such as, for example, the low-pressure mercury lamps at 185 nm, and especially at 254 nm. Truly high UV power is obtained only from high-pressure lamps (Xe, Hg), which then distribute their radiation over a greater range of wavelengths. The new excimer lasers have provided some new wavelengths for photochemical basic experiments, but at present are really only suitable in exceptional cases for an industrial process for cost reasons.
A new excimer radiator is described in the initially mentioned EP Patent Application, or also in the conference publication "Neue UV- und VUV-Excimerstrahler" (New UV and VUV Excimer Radiators) by U. Kogelschatz and B. Eliasson, distributed at the 10th conference of the Gesellschaft Deutscher Chemiker (Society of German Chemists), Photochemical Group, in Wurzburg (FRG), 18-20th Nov. 1987. This new type of radiator is based on the fact that excimer radiation can be produced even in dark electrical discharges, a type of discharge which is used on an industrial scale in the generation of ozone. In the current filaments of this discharge, which are
present only briefly (&lt;1 microsecond), noble gas atoms are excited, by electron impact, which further react to excited molecule complexes (excimers). These excimers live for only a few 100 nanoseconds and, when they decay, output their bonding energy in the form of UV radiation.
The construction of an excimer radiator of this type essentially corresponds to that of a classic ozone generator, right down to the power supply, with the essential difference that at least one of the electrodes and/or dielectric layers delimiting the discharge space is transmissive for the radiation generated.